This invention relates to an image inputting method and apparatus for displaying an image through a lenticular lens device.
A lenticular lens system is proposed as a system for realizing a stereoscopic image display of the so-called multi-eye type by which a stereoscopic image can be visually observed from multi-directional points of view without glasses.
For example, U.S. Pat. No. 3,895,867 discloses a lenticular lens system wherein a negative film is photographed by means of a plurality of cameras spaced by a distance equal to a parallax and is printed onto a photographic film by way of a lens plate on which a plurality of lenticular lenses are arranged to obtain a so-called lenticular print which has a stereoscopic visual effect.
Meanwhile, also an attempt to combine a lenticular lens device with a television set to realize a stereoscopic television system has been made. In particular, Japanese Patent Laid-Open Application No. Heisei 3-97390 discloses a system wherein a television image is outputted compositely to a rear face of a lenticular lens device having a plurality of lenticular lenses arranged at a predetermined pitch P.
The first prior art system described above requires photographing by means of a camera using a film and printing onto photographic paper through the lenticular lens system. Also a dark room is required for development and printing.
Further, the first prior art system described above relies, in regard to what construction of images produced under the lenticular lens system allows stereoscopic vision with the two eyes, upon the reciprocity of image formation that original different images having a parallax between them are visually observed by the two eyes if images obtained by forming and printing negative images spaced by a distance equal to the parallax through a lenticular lens system are visually observed through the same lenticular lens system, but a method of producing an image to be placed directly below a lenticular lens system is not proposed by the lenticular lens system of the first prior art document described above.
It is to be noted that geometrical characteristics of such images projected by way of a lens system as are obtained by the first prior art lenticular lens system are disclosed in "Geometrical Characteristics of Stereoscopic Images of Continuous Visual Area Lens Plate", Production Research, Vol. 41, No. 11, November 1989, and it is reported in the document that the pitch of images obtained by projection is a little greater than the pitch p of the lenticular lenses in the direction of the arrangement of the lenticular lenses. The document of the first prior art lenticular lens system does not disclose a method of forming images to be placed immediately below lenses.
For the second prior art system, a method is reported in "50-Inch Multi-Eye Stereoscopic Television without Glasses", Journal of the Japanese Television Engineering Society, Vol. 45, No. 11. According to the report, images are arranged on the rear face of the lenticular lens system such that, in order to compose images of n cameras which photograph from different points of view, picture elements of the totaling n cameras are successively arranged with picture elements from a camera allocated to one pitch of the lenticular lenses while the other n-1 picture elements per one camera are abandoned. It is further reported that, according to the method, one of n picture elements for one pitch is selectively displayed for one point of view by the lenticular lens system and different images are displayed on the two eyes.
Further, for further detailed construction of images, a manner in which picture elements are arranged is disclosed in Japanese Patent Laid-Open Application No. Heisei 3-97390 mentioned hereinabove. The prior art document discloses, in addition to a method wherein original n image data are collected each by 1/n by sampling to compose a single image of the original size similarly as in the document entitled "50-Inch Multi-Eye Stereoscopic Television without Glasses" mentioned hereinabove, another method wherein n different data for each one lenticular lens, that is, per one pitch of the lenticular lenses, are arranged in a transverse direction without performing sampling while a picture element is repeated by n times in the longitudinal direction of the lenticular lenses to obtain data of the size of n.times.n.
However, any of the prior art documents which discloses the second lenticular lens system does not disclose such a displacement in pitch as disclosed in the document "Geometrical Characteristics of Stereoscopic Images of Continuous Visual Area Lens Plate" mentioned hereinabove.
FIG. 16 indicates loci of beams of light passing from different picture elements through the centers of spherical phases of lenticular lenses where one pitch of the lenticular lenses corresponds to three picture elements so that the pitch of three picture elements just coincides with the pitch of the lenticular lenses. In FIG. 16, the lenticular lenses are arranged at the pitch of 0.5 mm and are shown in an enlarged view with the scale of 100:1. In this instance, images formed from picture elements A cannot be observed by a single eye at any position.
Further, a method of determining whether or not such a lenticular image display is appropriate upon actual observation of a display image has not been proposed as yet, and it cannot be avoided to directly determine whether or not there is a stereoscopic visual effect.
Further, since a moving picture is displayed, in the document "50-Inch Multi-Eye Stereoscopic Television without Glasses" mentioned hereinabove, as a signal of a composite image using a high definition television signal, the scanning direction (scanning line) of an output image on the rear face of the lenticular lens system is the horizontal direction of the screen, and also the arrangement of the lenticular lenses is the horizontal direction. Accordingly, an optimum scanning direction has not been proposed as yet.
For example, where an image printer of the thermal sublimation type having a line thermal head is used as an image output apparatus, the resolution is high in the thermal printing element arrangement direction of the head, but is low in the feeding direction. Consequently, if the feeding direction of the line thermal head is coincident with the arrangement direction of the lenticular lenses, then when it is tried to selectively observe one of adjacent picture elements in such a display as a stereoscopic visual display wherein lenticular lenses are employed, an adjacent picture element, that is, an image component of a different parallax, may possibly be mixed and have a bad influence upon the stereoscopic vision.
On the other hand, in the case of a line thermal head, the pitch of output picture elements is fixed, and where lenticular lenses are arranged in the line arrangement direction of the head, the lenses must be formed at a pitch corresponding to the arrangement pitch of heads and cannot be adjusted.